Chemical Phase Separation of Superconductive and Ferromagnetic Domains in ZnNNi3−xCox

Abstract

Various ZnNyNi3−xCox compounds with differing Co content, x, were synthesized, and their magnetic properties were investigated. Uniform solid solutions could not be obtained at low Co content (x2) the uniform ferromagnetic solid solution ZnNyNi3−xCox (with most likely y=0.5) formed. The phase separation behavior is intrinsic to the system, reflecting the existence of a miscibility gap in ZnNyNi3−xCox for the samples with x<2, and was shown not to be attributable to incomplete synthesis. In the two-phased samples, high-quality granular contact between the superconductor and ferromagnet has been realized, suggesting that the production of useful devices requiring high-quality contacts between superconductors and ferromagnets may be possible by making use of this two-phase situation.